Snacks have long been a household staple around the world and range from treats to dietary supplements. However, not too long ago a nutrition trend found chocolates, candies, ice cream, and other naturally and artificially sweetened confections, as well as potato chips, pretzels, corn chips, and the like, being replaced by more healthy products. The terms “low fat,” “no-fat,” and “light” have become the watch words of the health conscious in the '90s. The trend has seen the popularity of puffed snacks, sometimes referred to as popped grain snacks and especially those made of corn and rice, steadily climb.
Very successful products have been made in the form of cakes generally made of puffed corn or rice. While these products had a heretofore acceptable amount of crispiness, they suffered from an unpleasant texture, usually nearest the core of the cake, resulting in the product sticking in teeth. The products are hockey puck-shaped (uniform in all three dimensions) and lack the appealing visual texture of conventional snack foods. The size of these snack cakes is also relatively large in size (approximately a three to four-inch disk-shaped cake). This size, as a single portion, can lead to a substantial amount of waste for some consumers, especially children. To address the problem of waste, a “mini-cake,” or smaller version of the original cake (about a one to two-inch disk-shaped cake or cracker) was introduced. The problems of texture and appearance, however, remained.
Examples of methods for making conventional grain cake products are disclosed in the described methods of U.S. Pat. No. 4,888,180 to Wu. These cake-forming devices are most frequently used with rice as the cereal grain since rice is capable of relatively easy expansion into a self-supporting cake. Statistics show that the availability and versatility of rice have not only made it an industry favorite, but a consumer favorite as well. The annual world rice harvest in the early 1990s exceeded 510 million metric tons, an increase of about 30 percent over the average during the period from 1979 to 1981. Rice grains are extensively used as human food, constituting the principal food of almost one-half the human race. The leading rice producers are China, with 36 percent of world output in the early 1990s, and India, with 22 percent. In the United States, production averaged close to 7 million metric tons, with Arkansas, California, Louisiana, and Texas being the leading rice-producing states.
Rice puffing and, in general, cereal puffing (or cereal popping) methods are well established in the prior art. Generally, methods known in the art rely primarily on a moisture content in the grains for puffing. The moisture content can be varied by many processes, such as, drying, cooking, parboiling, and tempering. Examples of attempted improvements in processing methods are described in U.S. Pat. No. 4,281,593 to Gevaert, U.S. Pat. No. 4,328,741 to Yoshikazu, and U.S. Pat. No. 4,667,588 to Hayashi.
There are two generally practiced methods for expanding or puffing grains: (1) heating the kernels of grain until they become extensible (i.e. until the starch becomes amorphous or flowable) at which point further heating permits evaporation of moisture (and out-gassing of some minor amounts of other gases entrained in the grain) which causes expansion (bubble formation) in the amorphous starch; (2) heating the grain kernels to a flowable state at atmospheric pressure, then suddenly reducing the pressure (partial vacuum) again permitting enhanced vaporization and out-gassing, and again causing expansion (bubble formation) in the amorphous starch; and (3) heating the grain kernels to a flowable state in a chamber where pressure is permitted (or caused) to build, then suddenly reducing the pressure to atmospheric, permitting enhanced vaporization and out-gassing and again causing expansion (bubble formation) in the amorphous starch.
This latter method is most conventionally used to make rice cakes of both the larger and “mini” sizes. This latter method is carried out in what is commonly referred to as rice popping machines. These machines provide a chamber defined by heated chamber walls. Once the pre-puffed grain is placed in the chamber, it is closed to a pressure seal. The food starch is heated by contact with the chamber walls. The amount of food starch, i.e. the amount of grain kernels loaded into the chamber, relative to the volume of the chamber, and amount of expansion, cause the puffed product to generally conform in all three dimensions to the shape of the chamber.
One problem with conventional rice popping processes is that the filling of the entire volume of the popping chamber upon expansion may limit the bubble size formed, or full expansion of the bulk amount of the food starch, or both. This may account for a less than fully crisped product and a teeth-sticking texture of the resulting rice cake. It is certainly responsible for the hockey puck-shape of the product, which heretofore was thought to be desirable.
Another problem which exists in use of rice popping equipment is trying to balance providing sufficient time to present good conditions for full expansion of the food starch, while at the same time trying to minimize chamber residence time to achieve high production rates. To date, this balance has produced the conventional rice cakes discussed above.
It is well known that the degree and ease of puffing is affected by many factors such as: the type of grain, the type of preprocessing (e.g. milling), the condition of the grain (e.g. moisture content), and the type of starch contained in the grain. Another advancement in puffing food starch is to puff food starch which has been floured, and to extrude it into a discrete size and shape. Such extruded pieces are cooled and dried to a state of desired moisture content and hardness for acceptable handling and storage. To date, such puffing has been limited to oven puffing or deep frying. The resulting products, however, are relatively uniform throughout the snack piece, and provide a monolithic texture to the mouth when eating them. The same can be said for the products made from the more conventional process of extrusion puffing.
The inventor is unaware of a cake-type product ever being attempted using such pelletized stock. Further, it appears that prior to the present invention, it has never been contemplated to employ such a pelletized pre-product in a rice popping machine or related process.
In sum, despite the improvements being made in the field of making puffed snack cakes from food starches, in particular rice grain, insufficient attention has been given to improving the overall visual and physical texture (e.g. crispiness) and appearance of the product. The present invention addresses these issues as well as solving the problems discussed above and providing other advantages which will become apparent to those skilled in the art upon reading the accompanying specification and claims.